Really, this is only a nerf for pugging, which at most times can be a pain in the ass for most of us, especially when some of us don't have all day to try complete one heroic.
If you want the challenge, then simply run with a guild group, you won't get the buff. And also, as other posts have already stated the dungeons are easy now anyway, so will just make them less painful, and more time to do other stuff in game.
I'm not one to QQ bout the difficulty of heroics, as I honestly like the harder content over the aoe fest wrath was. But if it makes the dungeons faster and less likely to fail, with the few hours a week I get to play, then I will be much happier.